Well, in some fictional stories, it could be a case of mistaken identity. Maybe the bad guys thought she knew something valuable and tied her up to get information from her. Or perhaps it's a part of a rescue mission - type story, where she is tied up at the start and then her hero (maybe her husband) comes to save her. In a more comical scenario, it could be a result of a miscommunication or a bet gone wrong within a group of friends.
One reason could be a prank. For example, her friends might be playing a harmless joke on her. Another reason could be part of a performance, like in a theater play or a movie scene. It could also be in the context of a mystery or adventure game where she is 'trapped' as part of the plot.
One reason could be for a game. For example, a scavenger hunt - like game where she has to use her other senses to find things. Another reason might be for a performance, like a play or a magic show as I mentioned before. Or it could be part of a surprise party where her friends and family want to build up the suspense before revealing the celebration.
One reason might be a creative form of foreplay. In a consensual and loving relationship, couples may explore different ways to add excitement. Another could be as a form of punishment in a very light - hearted and joking way. For example, if he forgot an important date.
One reason could be that the reader has stumbled upon a secret. For example, if the story is set in a world of spies, the reader might have accidentally overheard some top - secret information and the villains want to keep him quiet.
Perhaps it's a themed party. The 'wife tied up' is part of a pirate - themed party where she's captured by the 'bad pirates' and the guests have to rescue her through various challenges and games. It could be a really fun and interactive way to engage everyone at the party.
It could be part of a prank by her friends. Maybe they wanted to play a joke on her or you. Another possibility is that she was involved in some sort of self - defense training and was practicing being in a restrained situation.
One reason could be to create a sense of vulnerability. When a woman is tied up in a movie, it makes her seem more helpless and in need of rescue, which can drive the plot forward. For example, in action movies, the villain might tie up the female lead to lure the hero into a trap.
This is a very concerning situation. One possible reason could be some kind of mental breakdown or extreme family conflict. Maybe the sons have some serious issues that they are not able to handle in a proper way and they resorted to this inappropriate and illegal behavior out of desperation or lack of proper communication skills.
One possible reason could be a misunderstanding. Maybe she thought he was in danger of doing something rash and tied him up to stop him. For example, if he was about to make a bad business deal without thinking clearly.
One possible story could be a prank gone wrong. Maybe the husband was trying to play a harmless joke on his wife, like a pretend 'kidnapping' scenario for fun. But then things got out of hand when she couldn't easily free herself and they both ended up having a big laugh about it once she was untied.
In a very imaginative story, there could be a magical or supernatural element. A soccer girl might have unknowingly entered a forbidden area on the soccer field that is protected by some magical creatures. These creatures don't understand human ways and see her as a threat, so they tie her up and use a sock to gag her to keep her from making noise that might attract other humans.